Hi Scott,
I am also facing same issue. When i am using border layout the page not display and console error is coming like 'Layout run failed'. when i am using 'fit' or 'anchor' layout the page is displayed but console error coming. ['Layout run failed'].

but my page design need to use border layout.

Note: ExtJs4 is working fine with same code. I am getting this issue When trying to integrate with ExtJs4.1

Check your viewport layout

I was seeing the same warning message and lack of rendering when using a 'border' layout in my panel.
I have a simple Viewport with just the single Panel added to items.
Then my panel has a border layout set with two child panels - one in the north and one centered.

By changing from border to vbox it renders without the error.

I started to move the border layout up to the viewport and then had a thought.

My viewport had no layout set in its config...so I guess it was using 'auto' ?

So I decided to specify my viewport layout as 'fit' and tried again...this time it renders just fine.

So it looks like (at least with 4.1.2a) that you need to explicitly set the layout at the viewport...especially if you are using a panel with a border inside it.

Hi guys. Using examples above i made implementation that works and looks fine in 4.2.1.
But then tree popup shown first time it throws an error[E] Layout run failed. After this it works fine. Just want to get rid of this error.